Display apparatus and method of controlling display apparatus

ABSTRACT

A display apparatus includes: a display unit that displays a first image on a display surface; a control unit that causes the display unit to display the first image on the display surface; an object processing unit that generates a display object; and a storage unit. The control unit generates a second image by combining the display object generated by the object processing unit with the first image displayed on the display surface, and causes the display unit to display the second image. The storage unit stores first display data which represents the first image displayed on the display unit. The storage unit also stores second display data which represents the second image in association with the first display data.

CROSS-REFERENCE

The entire disclosure of Japanese Patent Application No. 2016-170492,filed Sep. 1, 2016 is expressly incorporated by reference herein.

BACKGROUND 1. Technical Field

The present invention relates to a display apparatus and a method ofcontrolling the display apparatus.

2. Related Art

In the related art, there are known systems in which content oftextbooks is displayed through operations of teachers on displayapparatuses such as electronic blackboards displaying educationalmaterials and students are caused to input answers to questions (forexample, see JP-A-2012-226186). In the system of JP-A-2012-226186,content of a textbook designated by a teacher is displayed on anelectronic blackboard, a question is displayed on the electronicblackboard through an operation by the teacher, and an answer of astudent input into a student's terminal is displayed.

JP-A-2012-226186 discloses an example in which a designated page in thetextbook that has a plurality of pages is displayed. However, the sizeof one page in the textbook is larger than a range which can bedisplayed by a display apparatus in many cases. For example, when adisplay region displayed by a display apparatus is horizontally long anda textbook is a vertically long document, there is a possibility of oneentire page of the textbook not being all displayable at a time. Inaddition, even when content data other than textbooks is displayed, thesame problem can arise. In this case, a part of the content data is cutand displayed. However, a display state of the content data displayedonce is desired to be reproduced, it is necessary to specify a displayedrange in the content data.

SUMMARY

An advantage of some aspects of the invention is to display content datawhich has content exceeding a range displayed by a display apparatus andsubsequently to easily reproduce a display state of the content data.

An aspect of the invention is directed to a display apparatus including:a display unit that displays a first image on a display surface; acontrol unit that causes the display unit to display the first image onthe display surface; an object processing unit that generates a displayobject; and a storage unit. The control unit generates a second image bycombining the display object generated by the object processing unitwith the first image displayed on the display surface and causes thedisplay unit to display the second image. The storage unit stores firstdisplay data which represents the first image displayed on the displayunit. The storage unit also stores second display data which representsthe second image in association with the first display data.

According to the aspect of the invention, the display apparatus storesthe first image displayed as the first display data and stores thesecond image displayed in such a manner that the display object iscombined with the first image as the second display data. Thus, thedisplay apparatus can easily reproduce a state in which first image isdisplayed. In addition, the display apparatus can easily reproduce astate in which the display object is combined and displayed and a statein which the display object is not combined.

In the display apparatus according to the aspect of the invention, thecontrol unit may generate the first display data and the second displaydata corresponding to an image equivalent to one surface and displayedon the display surface by the display unit.

According to the aspect of the invention with this configuration, thedisplay state of the first image can easily be reproduced using data ofan image equivalent to one surface displayed on the display surface bythe display apparatus.

In the display apparatus according to the aspect of the invention, whenthe control unit causes the display unit to display the first image, thecontrol unit may generate the first display data and store the firstdisplay data in the storage unit.

According to the aspect of the invention with this configuration, sincethe display apparatus stores the first display data in a state beforethe display of the display object, the display apparatus can easilyreproduce the display state of the first image. In addition, in regardto the first image displayed by the display apparatus, the first displaydata can be stored without omission.

In the display apparatus according to the aspect of the invention, whenthe control unit combines the display object generated by the objectprocessing unit with the first image and causes the display unit todisplay the display object, the control unit may generate the firstdisplay data and the second display data and store the first displaydata and the second display data in the storage unit.

According to the aspect of the invention with this configuration, whenthe display object is combined with the first image, the displayapparatus generates the first display data in the state in which thedisplay object is not combined and the second display data in the statein which the display object is combined. Therefore, in regard to thefirst image displayed by the display apparatus, the first display dataand the second display data can be stored without omission, and thus thedisplay state of the first image can easily be reproduced.

In the display apparatus according to the aspect of the invention, whenan instruction not to display the display object generated by the objectprocessing unit is input, the control unit may cause the display unit todisplay an image based on the first display data stored in the storageunit.

According to the aspect of the invention with this configuration, thedisplay apparatus can efficiently perform a process of not displayingthe display object using the first display data.

In the display apparatus according to the aspect of the invention, thestorage unit stores a plurality of pieces of the second display data inassociation with one piece of first display data.

According to the aspect of the invention with this configuration, forexample, the display apparatus can store the plurality of pieces ofsecond display data corresponding to a plurality of different displayobjects and thus can reproduce display states in which the plurality ofdifferent display objects are switched and combined in regard to onepiece of first display data.

In the display apparatus according to the aspect of the invention, in astate in which the control unit causes the display unit to display animage based on the first display data or the second display data storedin the storage unit, the control unit may combine the image based on thefirst display data or the second display data as the display object andcause the display unit to display the display object.

According to the aspect of the invention with this configuration, thedisplay apparatus can combine the first image data and the second imagedata with other images as display objects and display the images. Thus,it is possible to reproduce the display state of the first image invarious forms.

In the display apparatus according to the aspect of the invention, thecontrol unit may cut a part of content data and cause the display unitto display the first image based on the cut content data.

According to the aspect of the invention with this configuration, it ispossible to easily reproduce a display state in which the part of thecontent data is displayed by the display apparatus. Therefore, whencontent of the content data is larger than a range which can bedisplayed on the display surface, the display state of the content datacan be reproduced without performing a work of specifying a displayedrange.

The display apparatus according to the aspect of the invention mayfurther include a detection unit that detects an operation. The objectprocessing unit may generate the display object in response to theoperation detected by the detection unit.

According to the aspect of the invention with this configuration, it ispossible to generate the display object in response to the operation andcombine the display object with the first image to display the displayobject.

The display apparatus according to the aspect of the invention mayfurther include a position detection unit that detects a positioninstruction operation. The detection unit may acquire an instructionposition of the position instruction operation detected by the positiondetection unit. The object processing unit may generate the displayobject based on the instruction position acquired by the detection unit.

According to the aspect of the invention with this configuration, it ispossible to generate the display object in accordance with the positioninstruction operation and combine the display object with the firstimage to display the display object.

In the display apparatus according to the aspect of the invention, thedisplay unit may include a projection unit displaying an image byprojecting image light to the display surface. The position detectionunit may detect the position instruction operation in a projectionregion to which the projection unit projects the image light.

According to the aspect of the invention with this configuration, aprojector projecting image light to the display surface can display thefirst image, detect the position instruction operation in a projectionregion of the projector, and generate and display the display object. Inaddition, it is possible to easily reproduce the display state of thefirst image displayed by the projector.

Another aspect of the invention is directed to a method of controlling adisplay apparatus including a display unit that displays an image on adisplay surface. The method includes: displaying a first image on thedisplay surface by the display unit; storing first display data whichrepresents the first image displayed by the display unit in a storageunit; generating a display object; generating a second image bycombining the generated display object with the first image displayed onthe display surface; displaying the second image; and storing seconddisplay data which represents the second image in association with thefirst display data in the storage unit.

The display apparatus to which the method of controlling the displayapparatus according to the aspect of the invention is applied stores thefirst image displayed as the first display data and stores the secondimage displayed in such a manner that the display object is combinedwith the first image displayed as the second display data. Thus, thedisplay apparatus can easily reproduce a state in which the first imageis displayed. In addition, the display apparatus can easily reproduce astate in which the display object is combined and displayed and a statein which the display object is not combined.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a diagram illustrating a configuration and an installationstate of a display system.

FIG. 2 is a block diagram illustrating apparatuses connected to aprojector.

FIG. 3 is a block diagram illustrating the projector and an instructor.

FIG. 4 is a schematic diagram illustrating a configuration of a storageunit and data stored in the storage unit.

FIG. 5 is a diagram illustrating a process of displaying a part ofcontent data.

FIG. 6 is a flowchart illustrating an operation of the projector.

FIG. 7 is a diagram illustrating an example of second display data.

FIG. 8 is a diagram illustrating an example of the second display data.

FIG. 9 is a diagram illustrating an example of the second display data.

FIG. 10 is a diagram illustrating an example of the second display data.

FIG. 11 is a diagram illustrating an example of the second display data.

FIG. 12 is a diagram illustrating a display example of the projector.

FIG. 13 is a diagram illustrating a display example of the projector.

FIG. 14 is a diagram illustrating a display example of the projector.

FIG. 15 is a diagram illustrating a display example of the projector.

FIG. 16 is a diagram illustrating a display example of the projector.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 is a diagram illustrating a configuration and an installationstate of a display system 1.

The display system 1 includes a projector 100 as a specific form of adisplay apparatus. In the display system 1, tablets 2 and 3 areconnected to the projector 100 (display apparatus) by wirelesscommunication lines so that data communication can be performed. Thenumber of tablets 2 and 3 included in the display system 1 is notlimited. In the embodiment, an example in which one tablet 2 and aplurality of tablets 3 are connected to the projector 100 will bedescribed.

The tablets 2 and 3 can be assigned to users who have different roles.For example, when the display system 1 is used in an education place, auser (for example, a teacher) who performs education uses the tablet 2and users (for example, students) who get education use the tablets 3.The user operating the tablet 2 or another user operates the projector100. In the embodiment, the user operating the tablet 2 operates theprojector 100 using an instructor 70.

FIG. 1 illustrates an installation state of the projector 100.

The projector 100 is installed above or obliquely above a screen SC andprojects an image toward the screen SC (display surface). The screen SCis a plate or a curtain fixed to a wall surface or erect to a surface ofa floor. The invention is not limited to this example and the wallsurface can also be used as the screen SC. In this case, the projector100 may be mounted on an upper portion of the wall surface used as thescreen SC.

The projector 100 may be connected to an image supply apparatus thatoutputs an image. The image supply apparatus is a server apparatus, apersonal computer (PC), or a media reproduction apparatus thatreproduces a digital versatile disk (DVD), a Blu-ray disc, or the like.In this case, the projector 100 projects an image to the screen SC basedon an analog image signal or digital image data output by the imagesupply apparatus. The projector 100 may read image data stored in astorage unit 60 (see FIG. 3) or an externally connected storage mediumand may display an image on the screen SC based on the image data.

The projector 100 projects an image to a projection region 10 of thescreen SC. The size of the projection region 10 can be adjusted by azoom function or the like of the projector 100. In the embodiment, anexample in which an image is projected to the projection region 10 withthe same size as the screen SC will be described. The projection region10 may be smaller than the screen SC.

The projector 100 detects an operation by the instructor 70. Theinstructor 70 is a pen-type input device which is gripped with a hand bythe user. The user grips a shaft portion 72 of the instructor 70 withhis or her hand and performs an operation of bringing the front endportion 71 of the instructor 70 into contact with the screen SC. Forexample, the user can perform an operation of bringing the front endportion 71 into contact with the screen SC for a given time. In thiscase, the projector 100 detects a position at which the front endportion 71 is brought into contact with the screen SC as an instructionposition. The user can perform an operation of moving the front endportion 71 while bringing the front end portion 71 into contact with thescreen SC. In this case, the projector 100 detects a trajectory in whichthe front end portion 71 is moved on the screen SC.

The projector 100 detects an operation performed using the instructor 70and reflects the detected operation in a display image on the screen SC.For example, the projector 100 detects an instruction positioninstructed with the front end portion 71 and realizes a graphical userinterface (GUI) operation of performing a function of the projector 100based on the coordinates of the instruction position. The projector 100generates and displays a display object such as a letter or a figurealong a trajectory of the instruction position of the front end portion71. A function of generating and displaying a display object is referredto as a drawing function.

The tablet 2 includes a touch panel 201 on its body with a flat plateshape. The tablet 3 includes a touch panel 301 in its body with a flatplate shape. The touch panels 201 and 301 have a configuration in whicha display screen with a liquid crystal display panel or an organic ELpanel and a touch panel detecting a touch operation are superimposed.The tablet 2 detects that a finger or a hand of the user is touched onthe touch panel 201. The tablet 3 detects that a finger or a hand of theuser is touched on the touch panel 301.

FIG. 2 is a functional block diagram illustrating the tablets 2 and 3.

The tablet 2 includes an interface (I/F) unit 211. The interface unit211 is connected to the projector 100.

The interface unit 211 may be a wired communication interface thatincludes a connector for wired connection wired-connected to an externalapparatus and an interface circuit corresponding to this connector.Specifically, the interface unit 211 may be an interface correspondingto a wired LAN, IEEE 1394, a USB, a mobile high-definition link (MHL:registered trademark), a high-definition multimedia interface (HDMI:registered trademark), or the like.

The interface unit 211 may be a wireless communication interface thatincludes an antenna, a radio frequency (RF) circuit, and amodulation/demodulation circuit. For example, the interface unit 211 maybe an interface corresponding to a wireless LAN (including WiFi(registered trademark)), Bluetooth (registered trademark), Miracast(registered trademark), or the like.

The interface unit 211 according to the embodiment is a wirelesscommunication interface capable of performing wireless LANcommunication.

The tablet 2 includes a control unit 212, a display unit 213, an inputunit 214, and a storage unit 220. These units and the interface unit 211are connected to each other by a bus 230. The control unit 212 includesa central processing unit (CPU), a random access memory (RAM), and aread-only memory (ROM) (none of which is illustrated). The control unit212 causes the CPU to execute a control program stored in the ROM and acontrol program stored in the storage unit 220 and controls each unit ofthe tablet 2.

The display unit 213 and the input unit 214 are connected to the touchpanel 201. The display unit 213 displays various screens on the touchpanel 201 under the control of the control unit 212. The input unit 214detects a touch operation on the touch panel 201 and outputs coordinatedata indicating the position of the detected operation to the controlunit 212.

The storage unit 220 stores a program to be executed by the control unit212 and various kinds of data in a nonvolatile manner. The storage unit220 stores image data 221 and setting data 222.

The image data 221 is display image data including an image or a letterto be displayed on the touch panel 201 by the display unit 213. Thecontrol unit 212 can cause the display unit 213 to display an imagebased on the image data 221. When image data transmitted by theprojector 100 is received by the interface unit 211, the control unit212 stores the image data as the image data 221 and displays an imagebased on the image data 221.

The setting data 222 includes information set in advance in regard to anoperation of the tablet 2. For example, the setting data 222 includesinformation regarding communication setting of the interface unit 211.Specifically, a media access control (MAC) address of the tablet 2, anInternet protocol (IP) address, a network name, and a service setidentifier (SSID) may be included. An SSID of an apparatus to which theinterface unit 211 is connected, a type of security setting, a passwordor a passkey, and a terminal name may be included. For example, thesecurity setting can be selected from a wired equivalent privacy (WEP),Wi-Fi protected access (WPA), and the like. The setting data 222 mayinclude information regarding communication setting of the interfaceunit 211 or may include information regarding communication setting of acommunication partner apparatus (the projector 100 or the like).

The control unit 212 performs wireless data communication with theprojector 100 through the interface unit 211 with reference to thesetting data 222.

The control unit 212 has a function of transmitting the image data 221to the projector 100. When this function is performed, the control unit212 reads the image data 221 from the storage unit 220 and transmits theimage data 221 to the interface unit 211 in response to an operationdetected on the touch panel 201. When image data is received from theprojector 100 by the interface unit 211, the control unit 212 stores thereceived image data as the image data 221.

When a touch operation is detected on the touch panel 201, the controlunit 212 has a function of transmitting data indicating an operationposition of the detected touch operation to the projector 100. When thisfunction is performed, the control unit 212 transmits the operationposition detected on the touch panel 201, for example, as coordinatedata of a coordinate system virtually set on the touch panel 201. Theoperation position detected by the control unit 212 is a relativeposition to an entire region in which the position detection isperformed on the touch panel 201. The control unit 212 transmits thecoordinate data indicating a relative position of the detection positionto the projector 100 through the interface unit 211.

The tablet 3 has the same configuration as the tablet 2. That is, thetablet 3 includes an interface (I/F) unit 311 connected to an externalapparatus such as the projector 100. The interface unit 311 has the sameconfiguration as the interface unit 211.

The tablet 3 includes a control unit 212, a display unit 313, an inputunit 314, and a storage unit 320. These units and the interface unit 311are connected to each other by a bus 330 so that data communication ispossible. The control unit 312 includes a CPU, a RAM, and a ROM (none ofwhich is illustrated) and causes the CPU to execute a control programstored in the ROM and a control program stored in the storage unit 320and controls each unit of the tablet 3.

The display unit 313 and the input unit 314 are connected to the touchpanel 301. The display unit 313 displays various screens on the touchpanel 301 under the control of the control unit 312. The input unit 314detects a touch operation on the touch panel 301 and outputs coordinatedata indicating the position of the detected operation to the controlunit 312.

The storage unit 320 stores a program to be executed by the control unit312 and various kinds of data in a nonvolatile manner. The storage unit320 stores image data 321 and setting data 322.

The image data 321 is display image data including an image or a letterto be displayed on the touch panel 301. The control unit 312 can causethe display unit 313 to display an image based on the image data 321.When image data transmitted by the projector 100 is received by theinterface unit 311, the control unit 312 stores the image data as theimage data 321 and displays an image based on the image data 321.

The setting data 322 includes information set in advance in regard to anoperation of the tablet 3. For example, the setting data 322 includesinformation regarding communication setting of the interface unit 311.Specifically, a MAC address of the tablet 3, an IP address, a networkname, and an SSID may be included. An SSID of an apparatus to which theinterface unit 311 is connected, a type of security setting, a passwordor a passkey, and a terminal name may be included. For example, thesecurity setting can be selected from a WEP, WPA, and the like. Thesetting data 322 may include information regarding communication settingof the interface unit 311 or may include information regardingcommunication setting of a communication partner apparatus (theprojector 100 or the like).

The control unit 312 establishes wireless communication with theprojector 100 with reference to the setting data 322 and performs datacommunication wirelessly with the projector 100. When the control unit312 transmits the image data 321 to the projector 100, the projector 100receives the image data 321 and projects an image based on the imagedata 321. The control unit 312 can also cause the display unit 313 todisplay the image based on the image data 321 to be transmitted to theprojector 100.

When a touch operation is detected on the touch panel 301, the controlunit 312 has a function of transmitting data indicating the operationposition of the detected touch operation to the projector 100. When thisfunction is performed, the control unit 312 transmits the operationposition detected on the touch panel 301, for example, as coordinatedata of a coordinate system virtually set on the touch panel 301. Theoperation position detected by the control unit 312 is a relativeposition to an entire region in which the position detection isperformed on the touch panel 301. The control unit 312 transmits thecoordinate data indicating a relative position of the detection positionto the projector 100 through the interface unit 311.

FIG. 3 is a functional block diagram illustrating the projector 100. InFIG. 3, the functional block diagram is illustrated along with afunctional block of the instructor 70.

The projector 100 includes an interface (I/F) unit 11 and an imageinterface (I/F) unit 12. The interface unit 11 and the image interfaceunit 12 are interfaces connected to an external apparatus. The interfaceunit 11 may be a wired communication interface that includes a connectorfor wired connection wired-connected to an external apparatus and aninterface circuit corresponding to the connector. Specifically, aninterface in conformity to a wired LAN, IEEE 1394, or a USB can beexemplified. The image interface unit 12 may be the same communicationinterface as the interface unit 11 or may be an image input interface.For example, a digital visual interface (DVI), a D terminal, an Sterminal, a composite, or a D-sub interface may be used. The imageinterface unit 12 may include an interface to which audio data is input.

The interface unit 11 and the image interface unit 12 may be wirelesscommunication interfaces that each include an antenna, an RF circuit,and a modulation/demodulation circuit. For example, these interface unitmay be an interface corresponding to a wireless LAN (including WiFi),Bluetooth, Miracast, or the like.

The interface unit 11 transmits and receives various kinds of data toand from an external apparatus under the control of the control unit 30to be described below. The interface unit 11 inputs and outputs dataregarding projection of an image and data or the like for setting anoperation of the projector 100.

The interface unit 11 according to the embodiment includes a wirelessLAN interface and performs wireless data communication with the tablets2 and 3 under the control of the control unit 30. The interface unit 11is connected to a communication line and can communicate with anexternal apparatus (a server) (not illustrated).

For example, the image interface unit 12 is connected to theabove-described image supply apparatus so that digital image data or ananalog image signal is input. The projector 100 can project an imagebased on the digital image data or the analog image signal input to theimage interface unit 12. In the embodiment, the digital image data isinput to the image interface unit 12.

The projector 100 includes a projection unit 20 (a display unit) thatforms an optical image. The projection unit 20 includes a light sourceunit 21, a light modulation device 22, and a projection optical system23. The light source unit 21 includes a light source formed of a xenonlamp, an ultra-high pressure mercury lamp, a light emitting diode (LED),or a laser light source. The light source unit 21 may include areflector and an auxiliary reflector that guide light emitted by thelight source to the light modulation device 22. Further, the projector100 may include a lens group (not illustrated) for improving opticalcharacteristics of projected light, a polarizing plate, or a modulatedlight element that reduces an amount of light emitted by the lightsource along a route reaching the light modulation device 22.

The light modulation device 22 includes three transmissive liquidcrystal panels corresponding to, for example, the three primary colorsof RGB and modulates light transmitted through the liquid crystal panelsto generate image light. Light from the light source unit 21 isseparated into three pieces of color light of RGB and the pieces ofcolor light are incident on the corresponding liquid crystal panels. Thepieces of color light that pass through the liquid crystal panels andare modulated are combined by a combination optical system such as across dichroic prism to exit to the projection optical system 23.

The projection optical system 23 guides the image light modulated by thelight modulation device 22 in the direction of the screen SC and formsan image on the screen SC. The projection optical system 23 may includea zoom mechanism that expands or reduces a display image on the screenSC or a focus adjustment mechanism that adjusts a focus. When theprojector 100 is of a short focus type, a concave mirror that reflectsthe image light toward the screen SC may be included in the projectionoptical system 23.

The projection unit 20 is connected to a light source driving unit 45that turns on the light source unit 21 under the control of the controlunit 30 and a light modulation device driving unit 46 that operates thelight modulation device 22 under the control of the control unit 30. Thelight source driving unit 45 may have a function of adjusting an amountof light of the light source unit 21 by switching turning on and turningoff the light source unit 21.

The projector 100 includes an image processing system that processes animage to be projected by the projection unit 20. The image processingsystem includes the control unit 30 that controls the projector 100, thestorage unit 60, an input reception unit 17, an image processing unit40, the light source driving unit 45, and the light modulation devicedriving unit 46. A frame memory 41 is connected to the image processingunit 40 and a position detection unit 50 is connected to the controlunit 30. These units may be included in the image processing system.

The control unit 30 includes a CPU, a ROM, and a RAM (not illustrated)and controls the projector 100 by causing the CPU to execute a basiccontrol program stored in the ROM. The CPU of the control unit 30executes a control program 61 stored in the storage unit 60 (see FIG. 4)and processes data such as setting data 62 and content data 63 stored inthe storage unit 60.

The storage unit 60 stores a program to be executed by the CPU includedin the control unit 30 and various kinds of data to be processed by thecontrol unit 30 in a nonvolatile manner.

FIG. 4 is a schematic diagram illustrating a configuration of thestorage unit 60 and data stored in the storage unit 60.

The storage unit 60 according to the embodiment stores, for example, thecontrol program 61, the setting data 62, and the content data 63. Adisplay data storage unit 64 is formed in the storage unit 60.

The control program 61 is a program executed by the control unit 30.

The setting data 62 includes information set in advance in regard to anoperation of the projector 100. For example, the setting data 62includes information regarding communication setting of the interfaceunit 11. Specifically, the MAC address of the interface unit 11, an IPaddress, a network name, and an SSID may be included. The SSID ofapparatus (including the tablet 2 or 3) to which the interface unit 11is connected, a type of security setting, a password or a passkey, and aterminal name may be included. For example, the security setting can beselected from a WEP, WPA, and the like. The setting data 62 may includeinformation of identifying the tablets 2 and 3 connected to theinterface unit 11. For example, unique IDs or the like assigned inadvance to the tablets 2 and 3 may be included. As will be describedbelow, the setting data 62 may include information regarding a detectionresolution of a touch operation on the touch panel 201 of the tablet 2and a detection resolution of a touch operation on the touch panel 301of the tablet 3. The setting data 62 may include information regardingan apparatus connected to the image interface unit 12.

The content data 63 is image data such as still image data and movingimage (video) data. The control unit 30 can cause the projection unit 20to project an image based on the content data 63. The content data 63may include a plurality of pieces of image data. The control unit 30 mayacquire image data input to the interface unit 11 or the image interfaceunit 12 and store the image data as the content data 63 in the storageunit 60. Each piece of image data included in the content data 63 may bedata to which audio data is added. The content data 63 may include theimage data and the audio data in association therewith.

The display data storage unit 64 is a virtual storage unit installed ina storage region of the storage unit 60. The display data storage unit64 may be a different storage unit from the storage unit 60.

The display data storage unit 64 stores first display data 601 andsecond display data 602 in association therewith. The first display data601 is image data of a image to be projected (displayed) by theprojection unit 20 under the control of the control unit 30. The seconddisplay data 602 is data of an image in which a display object generatedby the object processing unit 34 to be described below is combined in astate in which the projection unit 20 projects the image correspondingto the first display data 601. The second display data 602 is stored inassociation with input terminal data 603. The first display data 601,the second display data 602, and the input terminal data 603 will bedescribed below.

The image processing unit 40 processes the image data under the controlof the control unit 30 and outputs an image signal to the lightmodulation device driving unit 46. Processes performed by the imageprocessing unit 40 are a process of discriminating a 3D (stereoscopic)image from a 2D (planar) image, a resolution conversion process, a framerate conversion process, a distortion correction process, a digital zoomprocess, a color tone correction process, and a luminance correctionprocess. The image processing unit 40 performs a process designated bythe control unit 30 and performs a process using a parameter input fromthe control unit 30, as necessary. A plurality of processes among theforegoing processes can also be combined to be performed, of course.

The image processing unit 40 is connected to the frame memory 41. Theimage processing unit 40 processes image data input to the imageinterface unit 12 as input image data. When image data input to theinterface unit 11 is transmitted to the image processing unit 40 by thecontrol unit 30, the image processing unit 40 processes the image datatransmitted by the control unit 30 as input image data. The image datainput to the interface unit 11 includes, for example, image dataacquired from an external apparatus when the projector 100 communicateswith the external apparatus under the control of the control unit 30.Here, the external apparatus may be the tablet 2 or 3, a document camera(not illustrated) wired-connected to the interface unit 11, or a server(not illustrated) connected to the interface unit 11 via a communicationline. When the content data 63 stored in the storage unit 60 istransmitted to the image processing unit 40 by the control unit 30, theimage processing unit 40 processes the image data transmitted by thecontrol unit 30 as input image data.

The input image data processed by the image processing unit 40 isequivalent to content data according to the invention. The image datainput from the interface unit 11, the image data input from the imageinterface unit 12, and the content data 63 transmitted by the controlunit 30 are all equivalent to the foregoing content data.

The image processing unit 40 loads the input image data on the framememory 41 and draws an image on the frame memory 41. The imageprocessing unit 40 performs each of the foregoing processes on the imageloaded on the frame memory 41.

The image processing unit 40 reads the processed image data from theframe memory 41, generates image signals of R, G, and B corresponding tothe image data, and outputs the image signals to the light modulationdevice driving unit 46. For example, when the image data input to theimage interface unit 12 is moving image data configured with consecutiveframes, the image processing unit 40 loads each frame on the framememory 41. In this case, the image processing unit 40 sequentially loadsthe frames input from the image interface unit 12 on the frame memory 41and causes the projection unit 20 to project the frames.

The light modulation device driving unit 46 is connected to the liquidcrystal panels of the light modulation device 22. The light modulationdevice driving unit 46 drives the liquid crystal panels based on theimage signals input from the image processing unit 40 and draws an imageon each liquid crystal panel.

The input reception unit 17 is connected to a remote control lightreception unit 18 and an operation panel 19 and detects an operation viathe remote control light reception unit 18 and the operation panel 19.The remote control light reception unit 18 and the operation panel 19function as input devices.

The remote control light reception unit 18 receives an infrared signaltransmitted in response to a button operation by a remote controller(not illustrated) used by a user of the projector 100. The remotecontrol light reception unit 18 decodes the infrared signal receivedfrom the remote controller, generates operation data indicatingoperation content in the remote controller, and outputs the operationdata to the control unit 30.

The operation panel 19 is installed on an external casing of theprojector 100 and includes various types of switches and indicatorlamps. The input reception unit 17 appropriately turns on and off theindicator lamps of the operation panel 19 in accordance with anoperation state or a setting state of the projector 100 under thecontrol of the control unit 30. When the switches of the operation panel19 are operated, operation data corresponding to the operated switchesis output from the input reception unit 17 to the control unit 30.

The position detection unit 50 detects an instruction position of theposition instruction operation with the instructor 70. The positiondetection unit 50 includes units of a photographing unit 51, atransmission unit 52, a photographing control unit 53, a targetdetection unit 54, and a coordinate calculation unit 55.

The photographing unit 51 photographs a photographic range including atleast the projection region 10 and forms a photographic image. Theposition detection unit 50 detects an operation of the instructor 70 inthe photographic range of the photographing unit 51. Accordingly, thephotographic range of the photographing unit 51 is equivalent to adetection region of the position detection unit 50. In the embodiment,the detection region matches the projection region 10.

The photographing unit 51 includes an infrared image sensorphotographing infrared light and an interface circuit and performsphotographing using the infrared light. As the image sensor, one of aCCD and a CMOS can be used or another element can also be used. Aphotographic direction and a photographic range (angle of view) of thephotographing unit 51 cover a range in which the projection opticalsystem 23 projects an image to the screen SC in the same direction orsubstantially the same direction as the projection optical system 23,that is, the projection region 10. The photographing unit 51 outputsphotographic image data after performing the photographing.

The photographing control unit 53 controls the photographing unit 51such that the photographing unit 51 performs photographing under thecontrol of the control unit 30. The photographing control unit 53acquires the photographic image data of the photographing unit 51 andoutputs the photographic image data to the target detection unit 54. Animage of infrared light emitted by the instructor 70 is shown in thephotographic image data obtained using the infrared light by thephotographing unit 51.

The transmission unit 52 transmits a synchronization infrared signal tothe instructor 70 under the control of the photographing control unit53. The transmission unit 52 includes a light source such as an infraredLED and turns on and off the light source under the control of thephotographing control unit 53.

The target detection unit 54 detects an image of the infrared lightshown in the photographic image data of the photographing unit 51 anddetects the coordinates of a position of the instructor 70 in thephotographic image data. The target detection unit 54 determines whetherthe front end portion 71 of the instructor 70 comes into contact withthe screen SC. Based on a determination result, the target detectionunit 54 generates touch information indicating whether the front endportion 71 comes into contact with the screen SC. A method ofdetermining whether the front end portion 71 of the instructor 70 comesinto contact with the screen SC will be described below.

The coordinates of the position of the instructor 70 detected by thetarget detection unit 54 are coordinates in the photographic image dataof the photographing unit 51.

The coordinate calculation unit 55 converts the coordinates of theposition detected by the target detection unit 54 into coordinates onthe screen SC. More specifically, the coordinate calculation unit 55converts the coordinates of the position detected by the targetdetection unit 54 into coordinates at which an entire projection image(display image) to be projected to the screen SC is assumed to be areference.

A relation between the photographic image of the photographing unit 51and the projection image to be projected by the projection unit 20 isaffected by various components such as a distance between the projector100 and the screen SC, a zoom magnification in the projection opticalsystem 23, an installation angle of the projector 100, and a distancebetween the photographing unit 51 and the screen SC. Based on a resultof calibration performed beforehand, the coordinate calculation unit 55calculates the coordinates at which the projection image on the screenSC is a reference on the basis of the coordinates detected from thephotographic image data by the target detection unit 54. The coordinatescalculated by the coordinate calculation unit 55 are processed ascoordinates of an instruction position.

In the calibration, a predetermined pattern image is projected from theprojection unit 20 to the screen SC under the control of the controlunit 30 and the photographing unit 51 photographs the displayed patternimage. Then, based on the pattern image photographed by thephotographing unit 51, the control unit 30 calculates a coordinateconversion parameter indicating a correspondence relation betweencoordinates in photographic image data and coordinates on the displayimage of the screen SC. The control unit 30 includes the calculatedcoordinate conversion parameter in, for example, the setting data 62 tostore the coordinate conversion parameter in the storage unit 60. Thecoordinate calculation unit 55 can perform a process of converting thecoordinates detected by the target detection unit 54 using thecoordinate conversion parameter stored in the storage unit 60.

Here, the coordinates converted by the coordinate calculation unit 55are coordinates on the display image of the screen SC, can be said to becoordinates in an image formed in the light modulation device 22, andcan be said to be coordinates in an image drawn in the frame memory 41by the image processing unit 40. Accordingly, the position detectionunit 50 outputs the coordinates of the instruction position in which theimage of the frame memory 41 is a reference to the control unit 30.

The instructor 70 includes a control unit 73, a transceiver unit 74, anoperation switch 75, and a power unit 76. These units are accommodatedin the shaft portion 72 (see FIG. 1).

The control unit 73 is connected to the transceiver unit 74 and theoperation switch 75 and detects an ON/OFF state of the operation switch75. The operation switch 75 is disposed at the front end portion 71 ofthe instructor 70 and is turned on when the front end portion 71 istightly pressed against the screen SC. The transceiver unit 74 includesa light source such as an infrared LED and a light reception elementthat receives infrared light, turns on and off the light source underthe control of the control unit 73, and outputs a signal indicating alight reception state of the light reception element to the control unit73.

The power unit 76 includes a battery or a secondary cell as a powersource and supplies power to the units, the control unit 73, thetransceiver unit 74, and the operation switch 75. The instructor 70 mayinclude a power switch that turns on/off power supply from the powerunit 76.

A method of specifying a position of the instructor 70 from photographicimage data of the photographing unit 51 through mutual communication ofthe position detection unit 50 and the instructor 70 will be described.

When an operation is detected with the instructor 70, the control unit30 of the projector 100 controls the photographing control unit 53 andcauses the transmission unit 52 to transmit a synchronization signal.That is, the photographing control unit 53 turns on the light source ofthe transmission unit 52 at a predetermined period under the control ofthe control unit 30. The infrared light periodically emitted by thetransmission unit 52 functions as a synchronization signal forsynchronizing the position detection unit 50 with the instructor 70.

On the other hand, after power starts to be supplied from the power unit76 and the control unit 73 of the instructor 70 performs a predeterminedinitialization operation, the transceiver unit 74 receives the infraredlight emitted by the transmission unit 52 of the projector 100. When thetransceiver unit 74 receives the infrared light periodically emitted bythe transmission unit 52, the control unit 73 causes the presetinstructor 70 to turn on (emits light) the light source of thetransceiver unit 74 in a unique lighting pattern in synchronization witha timing of the infrared light. The control unit 73 switches a lightingpattern of the transceiver unit 74 in accordance with an operation stateof the operation switch 75. Therefore, the target detection unit 54 ofthe projector 100 can determine an operation state of the instructor 70,that is, whether the front end portion 71 is tightly pressed against thescreen SC, based on a plurality of pieces of sequentially photographedphotographic image data.

The control unit 73 repeatedly performs the foregoing operation whilepower is supplied from the power unit 76. That is, the transmission unit52 periodically transmits the synchronization infrared signal to theinstructor 70 and the instructor 70 transmits a preset infrared signalin synchronization with the infrared signal transmitted by thetransmission unit 52.

The photographing control unit 53 performs control such that aphotographic timing by the photographing unit 51 matches a timing atwhich the instructor 70 is turned on. The photographic timing isdetermined based on a timing at which the photographing control unit 53turns on the transmission unit 52. The target detection unit 54 canspecify a pattern in which the instructor 70 is turned on according towhether the image of the light of the instructor 70 is shown in theplurality of pieces of sequentially photographed photographic imagedata. The target detection unit 54 determines whether the front endportion 71 of the instructor 70 is tightly pressed against the screen SCbased on the plurality of pieces of photographic image data andgenerates touch information.

The lighting pattern of the instructor 70 may be a unique pattern foreach entity of the instructor 70 or may include a pattern common to theplurality of instructors 70 and a unique pattern for each entity. Inthis case, when images of the infrared light emitted by the plurality ofinstructors 70 are included in the photographic image data, the targetdetection unit 54 can distinguish the images as images of the differentinstructors 70.

The control unit 30 realizes functions of a projection control unit 31,an input detection unit 32, a communication control unit 33, an objectprocessing unit 34, and a combination control unit 35 by reading andexecuting the control program 61 stored in the storage unit 60, andcontrols each unit of the projector 100.

The projection control unit 31 acquires operation content obtained whenthe user operates the remote controller based on the operation datainput from the input reception unit 17. The projection control unit 31controls the image processing unit 40, the light source driving unit 45,the light modulation device driving unit 46 in response to the operationperformed by the user and projects an image to the screen SC.

The projection control unit 31 controls the image processing unit 40such that the process of discriminating a 3D (stereoscopic) image from a2D (planar) image, the resolution conversion process, the frame rateconversion process, the distortion correction process, the digital zoomprocess, the color tone correction process, and the luminance correctionprocess described above are performed. The projection control unit 31controls the light source driving unit 45 in accordance with a processof the image processing unit 40 such that the amount of light of thelight source unit 21 is controlled.

The input detection unit 32 (a detection unit) detects an input involvedin drawing. The input detection unit 32 acquires the coordinates of theinstruction position output by the position detection unit 50. The inputdetection unit 32 outputs data indicating the coordinates acquired fromthe position detection unit 50 to the object processing unit 34.

When data of an operation position transmitted by the tablet 2 or 3 isreceived by the interface unit 11, the input detection unit 32 acquiresthe data of the operation position. The input detection unit 32 outputsthe acquired data of the operation position to the object processingunit 34. Here, the data of the operation position received from thetablet 2 or 3 may be converted into data which can be processed by theobject processing unit 34.

Thus, the input detection unit 32 detects a position instructionoperation using the instructor 70 to acquire the instruction positionand detects a position instruction operation by a touch of the tablet 2or 3 to acquire the instruction position.

As described above, the tablet 2 has the function of specifying anoperation position of a touch operation and transmitting coordinate dataindicating the operation position when the touch operation is detectedon the touch panel 201. The tablet 3 has the function of specifying anoperation position of a detected touch operation and transmittingcoordinate data indicating the operation position when the touchoperation is detected on the touch panel 301. The coordinate datatransmitted by the tablet 2 indicates coordinates in which the entireregion in which a position is detected on the touch panel 201 is areference. The input detection unit 32 converts the coordinate datareceived from the tablet 2 by the interface unit 11 into coordinate datain which a resolution of image data processed by the image processingunit 40 is a reference. Similarly, the coordinate data transmitted bythe tablet 3 indicates coordinates in which the entire region in which aposition is detected on the touch panel 301 is a reference. The inputdetection unit 32 converts the coordinate data received from the tablet3 by the interface unit 11 into coordinate data in which a resolution ofimage data processed by the image processing unit 40 is a reference.That is, the input detection unit 32 converts the coordinates of theoperation position detected by the tablet 2 or 3 into coordinates in animage drawn on the frame memory 41.

In the process converting the coordinates, the input detection unit 32uses data regarding the coordinates of the entire region in which aposition is detected on the touch panel 201. For example, a detectionresolution of a region in which a position is detected by the touchpanel 201, a position of the origin for each coordinate axis, andmaximum coordinate values are included. As in the touch panel 201, theinput detection unit 32 uses data regarding the coordinates of theentire region in which a position is detected on the touch panel 301.The input detection unit 32 uses data regarding the coordinates of theentire region in which a position is detected by the position detectionunit 50. The data is included in, for example, the setting data 62. Theinput detection unit 32 uses data regarding the resolution of image dataprocessed by the image processing unit 40. The data is included in, forexample, the setting data 62.

On the other hand, coordinate data of an instruction position output tothe control unit 30 by the position detection unit 50 is coordinates inan image drawn on the frame memory 41.

In this way, the input detection unit 32 can obtain the coordinates ofthe instruction position instructed by the instructor 70 and thecoordinates of the instruction position instructed through the touchoperation on the tablet 2 or 3 as coordinate data in which theresolution of image data processed by the image processing unit 40 is areference.

The control unit 30 can also perform a GUI operation mode in which a GUIoperation is realized based on the instruction position. While the GUIoperation mode is performed, the control unit 30 displays an image forthe GUI operation, such as a menu bar in the projection region 10. Theinput detection unit 32 determines whether there is an operation on anicon or the like of the menu bar based on the coordinate data of theinstruction position and performs a process based on a determinationresult. The control unit 30 can switch between the GUI operation modeand an operation mode which is not the GUI operation mode, that is, adrawing mode in which drawing or the like is performed based on theinstruction position. Hereinafter, an operation of the projector 100 inthe drawing mode will be described.

In the drawing mode, the input detection unit 32 outputs the coordinatedata of the instruction position to the object processing unit 34. Thecoordinate data of the instruction position includes the coordinate dataoutput by the position detection unit 50 and the coordinate dataobtained by converting the input detection unit 32 at the time ofreception of the coordinate data received by the interface unit 11 fromthe tablet 2 or 3. The input detection unit 32 can also output dataindicating an acquisition source of the coordinate data along with thecoordinate data to the object processing unit 34. For example, when thecoordinate data output by the position detection unit 50 is acquired andoutput to the object processing unit 34, the input detection unit 32outputs data indicating that the acquisition source of the coordinatedata is the position detection unit 50 to the object processing unit 34.The object processing unit 34 acquires the coordinate data output by theinput detection unit 32 and the data indicating the acquisition sourceof the coordinate data.

The communication control unit 33 controls communication of the tablets2 and 3 via the interface unit 11. The communication control unit 33performs control such as selection of one tablet 3 or a plurality oftablets 3 from the plurality of tablets 3 and transmission of the imagedata to the selected tablets 3.

The object processing unit 34 draws a letter or a figure based on thecoordinate data output by the input detection unit 32. For example, theobject processing unit 34 disposes a preset image or letter at aposition corresponding to the coordinate data output by the inputdetection unit 32. For example, the object processing unit 34 acquires atrajectory of the instruction position from the coordinate data outputby the input detection unit 32 and performs a process of generating adisplay object on the basis of the acquired trajectory. The displayobject includes, for example, letters (text) or a figure (image) such asa straight line, a curved line, a polygon. A process in which the objectprocessing unit 34 converts the trajectory of the instruction positioninto letters is referred to as a letter recognition process, and aprocess in which the object processing unit 34 generates an imageaccording to the coordinates of the instruction position is referred toas a drawing process.

A kind of display object is designated under the control of thecombination control unit 35. For example, the combination control unit35 switches between a letter recognition mode in which the letterrecognition process is performed by the object processing unit 34 andletters are input and the drawing mode in which the drawing process isperformed by the object processing unit 34. The letter recognition modeand the drawing mode can be switched through an operation detected bythe input detection unit 32. The object processing unit 34 generatestext as a display object in the letter recognition mode and generates animage as a display object in the drawing mode.

The display object generated by the object processing unit 34 istransmitted to the image processing unit 40 by the combination controlunit 35 and the image processing unit 40 combines the display objectwith the image on the frame memory 41. Thus, the image including thedisplay object is projected by the projection unit 20.

The combination control unit 35 controls the object processing unit 34such that the display object is generated based on the coordinate dataoutput by the input detection unit 32. When the display object generatedby the object processing unit 34 includes data of letters (text), thecombination control unit 35 may convert the text data into image dataand transmit the image data to the image processing unit 40. Inaddition, the object processing unit 34 may generate the display objectobtained by converting the text data into the image data.

The combination control unit 35 transmits the image data of the displayobject to the image processing unit 40. The combination control unit 35controls a process of superimposing the display object on the imagedrawn on the frame memory 41 by the image processing unit 40. The imageprocessing unit 40 performs a combination process of combining thedisplay object with the image of the frame memory 41 under the controlof the combination control unit 35. In the combination process, theimage processing unit 40 draws an image based on the image data of thedisplay object to be superimposed on the image drawn on the frame memory41 based on the input image data to form one image. After thecombination process, the frame memory 41 is in a state in which oneimage is stored. The combination control unit 35 controls a position atwhich the display object is disposed on the frame memory 41 by the imageprocessing unit 40 or a size of the display object.

When the image processing unit 40 performs the combination process, thecombination control unit 35 generates image data of the image stored inthe frame memory 41 before the combination and stores the image data asthe first display data 601 (see FIG. 4) in the storage unit 60. Thecombination control unit 35 generates image data of the image after thecombination process and stores the image data as the second display data602 in the storage unit 60 in association with the first display data601. The combination control unit 35 stores the input terminal data 603in association with the second display data 602.

The object processing unit 34 can acquire data indicating an acquisitionsource of the coordinate data along with the coordinate data from theinput detection unit 32. When the display object generated by the objectprocessing unit 34 is transmitted to the image processing unit 40, thecombination control unit 35 acquires the data indicating the acquisitionsource of the coordinate data. That is, the combination control unit 35acquires the data indicating the acquisition source of the coordinatedata used for the letter recognition process or the drawing process ofgenerating the display object along with the display object from theobject processing unit 34. The data indicating the acquisition source ofthe coordinate data is stored as the input terminal data 603 in thestorage unit 60. The input terminal data 603 generated whenever theobject processing unit 34 generates the display object or thecombination control unit 35 combines the display object. Accordingly, asa typical example, one piece of input terminal data 603 is stored tocorrespond to one piece of second display data 602, and thus the seconddisplay data 602 and the input terminal data 603 have one-to-onecorrespondence.

A timing at which the combination control unit 35 performs a process ofgenerating and storing the first display data 601 is arbitrary. In theembodiment, two examples will be described. In a first example, when theimage processing unit 40 loads an image on the frame memory 41 or animage of the frame memory 41 is projected, the combination control unit35 generates the first display data 601. In a second example, when theimage processing unit 40 performs the combination process, thecombination control unit 35 generates the first display data 601 basedon an image of the frame memory 41 before the combination.

In the first and second examples, the first display data 601 is notlimited to the input image data acquired by the image processing unit40. For example, when the control unit 30 reads image data stored as thefirst display data 601 or the second display data 602 in the storageunit 60 and the image data is transmitted to the image processing unit40, the image processing unit 40 loads the transmitted image data. Inthis case, the combination control unit 35 can store the image data ofthe image loaded on the frame memory 41 by the image processing unit 40as the first display data 601.

The second display data 602 is image data of an image of the framememory 41 after the image processing unit 40 performs the combinationprocess. When the image processing unit 40 combines the display object,the combination control unit 35 generates the second display data 602based on the combined image. When the object processing unit 34generates the display object, the input terminal data 603 indicates anapparatus (device) performing an input. Accordingly, an apparatuscorresponding to the display object included in the second display data602 can be specified with the input terminal data 603. For example, acase will be assumed in which the object processing unit 34 generatesthe display object based on the instruction position of a touchoperation on the tablet 2 and the combination control unit 35 combinesthe display object. In this case, the image data of the combined imageis stored as the second display data 602 and the input terminal data 603indicating the tablet 2 is stored in association with the second displaydata 602.

FIG. 5 is a diagram illustrating an operation of the projector 100 andillustrating a process of cutting and displaying a part of content data.Content data 63A illustrated in FIG. 5 is one specific example of thecontent data 63 and is letter data. The content data 63A has a sizelarger than a size which can be displayed by the projector 100.Specifically, in both the transverse direction (horizontal direction)and the longitudinal direction (vertical direction) of the content data63A, the size is larger than the size which can be displayed by theprojector 100, that is, the size of an image drawn on the frame memory41. Here, the size indicates the number of dots (the number of pixels)of image data in the transverse direction or the longitudinal direction.The size of the frame memory 41 is suitable for the number of pixels orthe number of dots which can be formed in the light modulation device 22included in the projection unit 20. Accordingly, the size of an imagedrawn on the frame memory 41 by the image processing unit 40 correspondsto the size of an image formed in the light modulation device 22. Morespecifically, a maximum size of an image which can be formed in thelight modulation device 22 is identical.

The content data 63A is an example of the content data 63 for learningand is specifically an educational material for mathematics.Mathematical problems are disposed on the left side of the content data63A and solutions to the problems are disposed on the right side of theproblems. The plurality of problems can be arrayed in the longitudinaldirection of the content data 63A. In the display system 1, a useroperating the tablet 2 can operate the projector 100 to sequentiallydisplay the problems and the solutions of the content data 63A andperform a mathematical lecture.

When the size of the input image data is different from the size whichcan be drawn on the frame memory 41, the image processing unit 40 has afunction of loading the entire input image data on the frame memory 41and drawing an image by expanding or contracting the input image data.Accordingly, the image processing unit 40 can contract the entirecontent data 63A and load the contacted content data 63A on the framememory 41. In this case, the entire content data 63A is contracted andprojected to a projection region of the screen SC.

The image processing unit 40 can also cut and display a part of theinput image data. For example, when the control unit 30 causes the imageprocessing unit 40 to designate a display magnification at the time ofloading the input image data on the frame memory 41, the imageprocessing unit 40 expands or contracts the input image data accordingto the designated display magnification. When the size of the inputimage data is larger than the size which can be loaded on the framememory 41 as the result obtained by expanding or contracting the inputimage data, the control unit 30 controls the image processing unit 40such that the process of cutting the input image data is performed. Inthis case, the control unit 30 cuts a range fitted to the size of theframe memory 41 from the input image data.

In the image processing unit 40, a displayable size is set as an upperlimit of the size of the input image data. The displayable size is thesize of the input image data which can be loaded on the frame memory 41.The image processing unit 40 according to the embodiment can perform adigital zoom process under the control of the control unit 30. Throughthe digital zoom process, the image processing unit 40 expands (extends)the input image data according to the magnification designated by thecontrol unit 30 to load the input image data on the frame memory 41.Accordingly, when the magnification of the digital zoom process islarger than one time, the upper limit of the size of the image datawhich can be loaded on the frame memory 41 is less than the size of theframe memory 41. The image processing unit 40 can determine whether thesize of the input image data exceeds the displayable size which is theupper limit of the size which can be loaded on the frame memory 41. Thedisplayable size is designated according to the magnification of thedigital zoom process designed by the control unit 30. The displayablesize may be set by the control unit 30 or the displayable size may beset in the image processing unit 40 according to the magnificationdesignated by the control unit 30. The size of the input image data andthe size of the frame memory 41 are expressed by, for example, aresolution or the number of dots. When the size of the input image dataexceeds the displayable size, the image processing unit 40 performs aprocess of cutting a portion equivalent to the displayable size from theinput image data.

For example, in regard to the content data 63A in FIG. 5, the imageprocessing unit 40 cuts display data 611. The size of the cut displaydata 611 is a size fitted to the displayable size. The displayable sizecorresponds to, for example, a display resolution of a liquid crystalpanel included in the light modulation device 22 or the number of pixelsof the displayable region set in the liquid crystal panel. The imageprocessing unit 40 may be configured to convert the resolution of thedisplay data 611 in conformity to the displayable region of the lightmodulation device 22 or the entire light modulation device 22 or performgeometric correction. In this case, the size of the display data 611 isdetermined so that the image processing unit 40 can easily process thedisplay data 611 to be suitable for the displayable size.

The position of the display data 611 in the content data 63A is notlimited. FIG. 5 illustrates an example of a case in which the imageprocessing unit 40 cuts the display data 611 when display of the contentdata 63A is started. Therefore, the display data 611 in FIG. 5 includesa top left corner portion which is a beginning position of the contentdata 63A.

The position of the display data 611 in the content data 63A, that is, acut position, can be designated under the control of the control unit30. The control unit 30 can set the position of the display data 611 cutfrom the content data 63A in response to an operation detected by theposition detection unit 50 or an operation on the tablet 2 or 3.

In a state in which the projector 100 displays an image based on thedisplay data 611, the control unit 30 changes the cut position of thecontent data 63A through an operation of the tablet 2 or 3 or theinstructor 70. In this case, the control unit 30 causes the inputdetection unit 32 to receive the operation performed with the tablet 2or 3 or the instructor 70. The control unit 30 newly sets a position atwhich the display data 611 is cut in the content data 63A according tothe operation received by the input detection unit 32. The control unit30 controls the image processing unit 40 such that the display data 611is cut at the newly set position and loaded on the frame memory 41. Thecontrol unit 30 switches the image displayed based on the display data611 to an image based on the display data 611 newly cut from the contentdata 63A.

In a state in which the image based on the display data 611 is displayedby the image processing unit 40, the control unit 30 can generate thedisplay object based on an operation received by the input detectionunit 32 and combine the display object with an image which is beingdisplayed. For example, in a state in which an image including amathematical problem is displayed based on the display data 611 in FIG.5, the projector 100 can draw a letter or an image and display theletter or the image to be superimposed on the mathematical problem.

The control unit 30 may be configured to control the image processingunit 40 such that the process of cutting a part of the content data 63can also be performed on input image data input to the interface unit 11and input image data input to the image interface unit 12.

When the display data 611 cut from the content data 63A is displayed,the control unit 30 generates and stores the first display data 601through a process to be described below. Through this process, thecontrol unit 30 stores image data of the display data 611 or image datagenerated from the display data 611 as the first display data 601A inthe storage unit 60. The first display data 601A is equivalent to onespecific example of the first display data 601. The first display data601A may be the display data 611. In addition, the first display data601A may be image data obtained by converting the resolution of thedisplay data 611 or data obtained by performing geometric correction onthe display data 611 or may be data obtained by causing the imageprocessing unit 40 to perform other image processing on the display data611.

FIG. 6 is a flowchart illustrating an operation of the projector 100.The operation illustrated in FIG. 6 is performed when the projector 100starts projecting an image.

The control unit 30 of the projector 100 determines whether display datais called from the storage unit 60 according to an operation detected bythe input detection unit 32 or previous setting (step S11). The displaydata of the storage unit 60 includes the first display data 601 and thesecond display data 602. A case in which no display data is calledcorresponds to a case in which an image is displayed based on thecontent data 63 and a case in which an image is displayed based on theinput image data input to the interface unit 11 or the image interfaceunit 12. Here, a case in which the content data 63 is read to display animage will be described as an example. In step S11, the combinationcontrol unit 35 determines whether the first display data 601 or thesecond display data 602 is called. This determination is performed basedon whether an instruction to call the first display data 601 or thesecond display data 602 is input through an operation detected by theinput detection unit 32. When the first display data 601 or the seconddisplay data 602 is not called, as will be described below, thecombination control unit 35 acquires the content data 63. Accordingly,when an instruction to read the content data 63 is input by the inputdetection unit 32 or when reading the content data 63 is set, it isdetermined that no display data is called from the storage unit 60. Whenit is determined that no display data is called from the storage unit 60(No in step S11), the control unit 30 acquires the content data 63 (stepS12).

The control unit 30 determines a range displayed in the acquired contentdata 63 and acquires data of the display range (step S13). For example,when the size of the content data 63 exceeds the displayable range as inthe content data 63A in FIG. 5, for example, the control unit 30 causesthe image processing unit 40 to cut a part of the content data 63 as inthe display data 611. The image processing unit 40 loads the data in thedisplay range cut in step S13 on the frame memory 41 and draws an imageon the frame memory 41. When the size of the content data 63 is equal toor less than the displayable range, the control unit 30 acquires theentire content data 63 as the data in the display range. In this case,the control unit 30 controls the image processing unit 40 such that thecontent data 63 can be expanded, loaded on the frame memory 41, anddrawn. The control unit 30 controls the image processing unit 40 suchthat an image is drawn in a part of the frame memory 41 based on thecontent data 63 and a region not drawn around the drawn image may be setwith black. Since the black region is a region in which image light isnot projected by the projection unit 20, the black region does not havean effect on display of the screen SC.

The control unit 30 generates the first display data 601 which is imagedata of the image drawn on the frame memory 41 by the image processingunit 40 and stores the first display data 601 in the storage unit 60(step S14). Thus, as will be described below, the image data in a statebefore the drawing is stored as the first display data 601.

Thereafter, the control unit 30 causes the projection unit 20 to displaythe image drawn on the frame memory 41 (step S15).

After the display is started, the control unit 30 determines whether aninput of the coordinate data is received by the input detection unit 32(step S16). The control unit 30 determines whether the coordinate datais input from the tablet 2 or 3 or the position detection unit 50 (stepS16). When one of an operation on the touch panel 201 of the tablet 2,an operation on the touch panel 301 of the tablet 3, and an operationwith the instructor 70 is performed, the input detection unit 32receives an input of the coordinate data. When the input detection unit32 receives the input of the coordinate data (Yes in step S16), thecontrol unit 30 determines whether the first display data 601 is alreadygenerated (step S17). In step S17, the control unit 30 determineswhether the image data of the image drawn on the frame memory 41 isalready stored as the first display data 601. In step S17, the controlunit 30 determines the image which is being displayed at the time ofreceiving the input of the coordinate data in step S16, that is, theimage drawn on the frame memory 41, as a target. In other words, it isdetermined whether the data of the image displayed immediately before aprocess of combining the display object in steps S20 and S21 to bedescribed below is performed is stored as the first display data 601.

When the control unit 30 determines that the image which is beingdisplayed is not stored as the first display data 601 (No in step S17),the control unit 30 stores the image data of the image in the framememory 41 as the first display data 601 in the storage unit 60 (stepS18) and causes the process to proceed to step S19. Conversely, when thecontrol unit 30 determines that the image which is being displayed isstored as the first display data 601 (Yes in step S17), the control unit30 causes the process to proceed to step S19.

In step S19, the control unit 30 specifies the device inputting thecoordinate data received by the input detection unit 32, that is, thedevice of the acquisition source of the coordinate data (step S19).

The control unit 30 causes the object processing unit 34 to generate thedisplay object based on the coordinate data (step S20). The control unit30 causes the combination control unit 35 to perform the process ofcombining the display object generated by the object processing unit 34with the image in the frame memory 41 (step S21). Here, the control unit30 generates the second display data 602 and stores the second displaydata 602 in the storage unit 60 based on the image data after thecombination in the frame memory 41 (step S22). For example, the data ofthe image combined in step S19 can be set as the second display data 602without change. In step S22, the control unit 30 stores the seconddisplay data 602 in the storage unit 60 in association with the firstdisplay data 601 stored in step S14.

Here, the control unit 30 generates the input terminal data 603indicating the device specified in step S17 and stores the inputterminal data 603 in the storage unit 60 in association with the seconddisplay data 602 generated in step S20.

The control unit 30 causes the projection unit 20 to project thecombined image combined in the frame memory 41 (step S23).

The control unit 30 causes the input detection unit 32 to determinewhether an operation of giving an instruction to convert the contentdata 63 which is being displayed or the range displayed in the contentdata 63 is performed (step S24). When the instruction to switch thedisplay is determined to be performed (Yes in step S24), the controlunit 30 returns the process to step S11.

When the instruction to switch the display is determined not to beperformed (No in step S24), the control unit 30 determines whether thedisplay is ended (step S25). When the display is not ended (No in stepS25), the control unit 30 returns the process to step S16.

Conversely, when the control unit 30 determines that the display data iscalled from the storage unit 60 (Yes in step S11), the control unit 30performs a process of displaying the first display data 601 or thesecond display data 602. First, the control unit 30 performs a processof selecting a display format of the first display data 601 or thesecond display data 602 (step S26).

As will be described below, the projector 100 can display the firstdisplay data 601 and the second display data 602 in a plurality ofdisplay formats. For example, “entire surface display” in which thefirst display data 601 or the second display data 602 is displayed inthe entire display region and “array display” in which a plurality ofpieces of first display data 601 or second display data 602 are arrayedand displayed in one display region can be selected. The display regionmay be a region in which drawing is possible in the frame memory 41 or adisplayable region which is a maximum region in which the lightmodulation device 22 can form an image. A region of the frame memory 41corresponding to the projection region 10 (see FIG. 1) may be set as thedisplay region. Here, when the control unit 30 controls the imageprocessing unit 40 such that a geometric correction process such astrapezoidal distortion correction is performed, a region in which animage can be drawn and formed is a region less than the displayableregion. In this case, the region in which an image can be drawn andformed is regarded as the displayable region. The control unit 30 canalso control the image processing unit 40 such that a display region inwhich the first display data 601 and the second display data 602 aredisplayed is limited to a part of the displayable region. In this case,the control unit 30 displays one piece or a plurality of pieces of firstdisplay data 601 or second display data 602 in the entire surfacedisplay or array display format to fall within the set display region.

In step S26, the control unit 30 designates a display format through anoperation received by the input detection unit 32 or according to presetcontent. When the display format is set in advance, data indicating thissetting is stored as, for example, the setting data 62 in the storageunit 60.

The control unit 30 selects the read display data through an operationreceived by the input detection unit 32 (step S27). The display dataselectable herein may be one of the first display data 601 and thesecond display data 602.

The control unit 30 reads the display data selected in step S27 from thestorage unit 60, controls the image processing unit 40, loads the framememory 41, and displays the display data (step S28). After the displayis started, the control unit 30 causes the process to proceed to stepS16.

In the operation of FIG. 6, the process of displaying the content data63, or the first display data 601 or the second display data 602 isperformed. When an image is displayed based on the content data 63, thefirst display data 601 is generated and stored in step S14. Therefore,the display data corresponding to all the images displayed under thecontrol of the control unit 30 is generated and stored.

When the display object is combined in step S21, the control unit 30generates and stores the first display data 601 in regard to the imagebefore the combination in step S17. When the display object is combinedin step S21 in the state in which the second display data 602 isselected and displayed in step S27, the second display data 602 which isbeing displayed is newly stored as the first display data 601. Then, thedata of the image after the combination of the display object in stepS21 is stored as the second display data 602. The first display data 601and the second display data 602 are stored in the storage unit 60 inassociation therewith. Accordingly, the storage unit 60 stores the firstdisplay data 601 and the second display data 602 in association with thesecond display data 602 obtained by combining the display object withthe second display data 602. The second display data 602 before thecombination of the display object may be stored as the first displaydata 601. As a result, the storage unit 60 stores the plurality ofpieces of second display data 602 in association with one piece of firstdisplay data 601 and further stores the second display data 602 combinedwith the display object in association with each piece of second displaydata 602. In other words, the storage unit 60 stores the first displaydata 601 and the plurality of pieces of second display data 602 in atree diagram form.

The storage unit 60 stores the input terminal data 603 in associationwith the second display data 602. The input terminal data 603 is datafor specifying a device outputting an instruction position used in theprocess of generating the display object included in the second displaydata 602. Accordingly, the second display data 602 including the displayobject generated through an operation on the tablet 2 can be retrievedand extracted from the storage unit 60 based on the input terminal data603.

FIG. 7 is a diagram illustrating the second display data 602A as anexample of the second display data 602. The second display data 602A isdata of an image obtained by combining a display object 621A with theimage of the first display data 601A (see FIG. 5).

When a display range is designated in the content data 63 in step S13and the display data 611 (see FIG. 5) is generated, an image based onthe display data 611 is displayed on the screen SC. When the firstdisplay data 601A is selected in step S27, the image based on the firstdisplay data 601A is displayed on the screen SC. This image is the sameas the image based on the display data 611.

Then, when the object processing unit 34 generates the display object621A according to an instruction position of an operation received bythe input detection unit 32 and combines the display object 621A, acombined image is projected to the screen SC. The control unit 30 storesdata of the combined image as the second display data 602A in thestorage unit 60. The control unit 30 stores the input terminal data 603for specifying a device inputting the instruction position which is abasis of the process of generating the display object 621A inassociation with the second display data 602A.

FIG. 8 is a diagram illustrating the second display data 602B as anexample of the second display data 602. The second display data 602B isdata of an image obtained by combining a display object 621B with theimage of the first display data 601A.

FIG. 9 is a diagram illustrating the second display data 602C as anexample of the second display data 602. The second display data 602C isdata of an image obtained by combining a display object 621C with theimage of the first display data 601A.

The second display data 602A, the second display data 602B, and thesecond display data 602C are generated through the processes ofcombining the display objects 621A, 6218B, and 621C with the firstdisplay data 601A, respectively. The storage unit 60 stores the seconddisplay data 602A, the second display data 602B, and the second displaydata 602C in association with the first display data 601A. The storageunit 60 stores the input terminal data 603 for specifying the deviceinputting the instruction position which is a basis of the process ofgenerating the display objects 621B and 621C in association with thepieces of second display data 602B and 602C.

Therefore, when an image before combination of the display object 621Ais displayed in a state in which the second display data 602A isgenerated and an image based on the second display data 602A isdisplayed, the projector 100 may display the first display data 601A.This is true for the pieces of second display data 602B and 602C. Thatis, a process of drawing the display objects 621A, 621B, and 621C andsubsequently displaying a state before the drawing can be performedquickly. In this process, for example, it is not necessary to designatethe positions or ranges of the display objects 621A, 621B, and 621Cwhich are displayed and give an instruction to erase the display.Therefore, a process of erasing or not displaying the display objects621A, 621B, and 621C can be performed through a simple operation. Thereis the advantage of not erasing other components included in the imageswhich are being displayed when the display objects 621A, 621B, and 621Care erased.

Specifically, the control unit 30 performs the foregoing process whenone of the display objects 621A, 621B, and 621C is generated andcombined by the object processing unit 34 and subsequently aninstruction to return (undo) the drawing of the object to the originalis detected by the input detection unit 32. In this case, only when theinstruction to return the drawing of the object to the original isdetected based on an input of a device specified by the input terminaldata 603, the control unit 30 may perform the foregoing process not todisplay the display object. That is, a device performing an operation ofgiving an instruction to erase the display object or not to display thedisplay object may function as a determination unit performingdetermination. In this case, the control unit 30 performs determinationbased on the input terminal data 603.

Further, another display object can also be combined with the seconddisplay data 602A, the second display data 602B, and the second displaydata 602C.

FIG. 10 is a diagram illustrating second display data 602D as an exampleof the second display data 602. The second display data 602D is data ofan image in which the display object 621D is combined with the imagedisplayed based on the second display data 602A (see FIG. 7). When thedisplay object 621D is combined in the frame memory 41 in a state inwhich the second display data 602A is selected and the second displaydata 602A is loaded to the frame memory 41 in step S27, the seconddisplay data 602D is generated in step S22. In this example, the seconddisplay data 602A which is data of an image before the combination ofthe display object 621D and the second display data 602D which is dataof an image after the combination are stored in the storage unit 60 inassociation therewith. The same data as the second display data 602A maybe stored as the first display data 601 in the storage unit 60.

FIG. 11 is a diagram illustrating second display data 602E as an exampleof the second display data 602. The second display data 602E is data ofan image in which the display object 621E is combined with the imagedisplayed based on the second display data 602C (see FIG. 8). In thisexample, the second display data 602C which is data of an image beforethe combination of the display object 621E and the second display data602E which is data of an image after the combination are stored in thestorage unit 60 in association therewith. The same data as the seconddisplay data 602B may be stored as the first display data 601 in thestorage unit 60.

FIG. 12 is a diagram illustrating a display example of the projector100.

In this example, the display objects 25A, 25B, and 25C are arrayed anddisplayed on the screen SC. The display object 25A is an image displayedbased on the second display data 602A and the display object 25B is animage displayed based on the second display data 602B. The displayobject 25C is an image displayed based on the second display data 602C.As exemplified in FIG. 12, in the projector 100, a display format inwhich images based on the second display data 602 stored in the storageunit 60 are arrayed and disposed in step S26 can be selected. Here,since the images based on the pieces of second display data 602A, 602B,and 602C are the display objects 25A, 25B, and 25C, for example, adisplay form such as movement or expansion/contraction of a displayposition can be changed through an operation on the tablet 2 or 3 or theinstructor 70. That is, the pieces of second display data 602A, 602B,and 602C which are data of a display image equivalent to one surface canbe processed as objects disposed in the projection region 10 or adisplay region. In this display format, an image corresponding to thefirst display data 601 stored in the storage unit 60 may be disposedwithout being limited to the second display data 602. An image based onthe first display data 601 and an image based on the second display data602 may be simultaneously disposed.

FIG. 13 is a diagram illustrating a display example of the projector100.

In this example, the display object 25D is displayed on the entireprojection region 10 of the screen SC. The display objects 25A, 25B, and25C are arrayed and displayed to be superimposed on the display object25D. The display object 25D is an image displayed based on the firstdisplay data 601A. As in the example of FIG. 13, the image based on thefirst display data 601 or the second display data 602 may be displayedas a display object and the image based on another first display data601 or second display data 602 may be displayed to be superimposed onthe display object.

FIG. 14 is a diagram illustrating a display example of the projector100.

This example is a display example in a state in which a new displayobject 621F is combined with the display object 25B in the display stateillustrated in FIG. 13. When a position instruction operation isperformed using the tablet 2 or 3 or the instructor 70 in the displayexample illustrated in FIGS. 12 and 13, the control unit 30 can performa process of generating and combining a display object. In this case, adisplay image before the combination of the display object, that is,image data of an image in which the display objects 25A, 25B, and 25Care superimposed on the display object 25D by the control unit 30, isstored as the first display data 601 in the storage unit 60. Then, thecontrol unit 30 stores the image data of the image after the combinationof the display object 25F as the second display data 602 in the storageunit 60.

Only a part of the projection region 10 of the screen SC can also beused as a display format in which a plurality of images based on thefirst display data 601 and/or the second display data 602 are disposedas display objects.

FIG. 15 is a diagram illustrating a display example of the projector100. In the example of FIG. 15, the display objects 25A, 25B, and 25Care disposed in a disposition region 27A disposed in a lower portion ofthe projection region 10 of the screen SC. The size and position of thedisposition region 27A can be included in the preset setting data 62(see FIG. 4).

In FIG. 16, the display objects 25A, 25B, and 25C are disposed in adisposition region 27B disposed on the right side of the region. Thesize and position of a disposition region are not limited to theexamples of the disposition regions 27A and 27B, but any size andposition can be set.

As described above, the projector 100 according to an embodiment towhich the invention is applied includes the projection unit 20 thatdisplays an image on the screen SC and the control unit 30 that causesthe projection unit 20 to display the image on the screen SC based onthe content data 63. The projector 100 further includes the objectprocessing unit 34 that generates a display object and the storage unit60. The control unit 30 combines the display object generated by theobject processing unit 34 with the image displayed on the screen SCbased on the content data 63 to display the display object. The controlunit 30 stores the first display data 601 which is data of the imagedisplayed based on the content data 63 by the projection unit 20 in thestorage unit 60. The control unit 30 also stores the second display data602 which is data of the image in which the display object is combinedwith the image of the first display data 601 in the storage unit 60 inassociation with the first display data 601. Thus, the projector 100stores the image displayed based on the content data 63 as the firstdisplay data 601 and the image displayed by combining the display objectwith the displayed image as the second display data 602. Accordingly,the projector 100 can easily reproduce a state in which the content data63 is displayed. The projector 100 can easily reproduce a state in whichthe display object is combined and displayed and a state in which nodisplay object is combined.

For example, in a state in which a part of the content data 63 is cut asthe display data 611 and an image based on the display data 611 isdisplayed, the display object 621A (see FIG. 7) can be generated anddisplayed in response to an operation received by the input detectionunit 32. In this case, the data of the image in the state before thecombination of the display object 621A is stored as the first displaydata 601A (see FIG. 5) in the storage unit 60. Therefore, by displayingan image based on the first display data 601A, it is possible to easilyreproduce the state before the combination of the display object 621A.Since the data of the image with which the display object 621A iscombined is stored as the second display data 602A, it is possible toeasily reproduce the image.

The control unit 30 generates the first display data 601 correspondingto an image equivalent to one surface displayed on the screen SC by theprojection unit 20 and the second display data 602. For example, in theframe memory 41, the data of the image drawn in a region correspondingto the projection region 10 may be set as the first display data 601 andthe second display data 602. Thus, it is possible to easily reproduce adisplay state of the content data 63 using the data of the imageequivalent to one surface displayed on the screen SC by the projector100.

When an image is displayed based on the content data 63 by theprojection unit 20, the control unit 30 generates the first display data601 and stores the first display data 601 in the storage unit 60. Thatis, the projector 100 stores the data of the image in the state beforecombination or the like of the display object is performed, as the firstdisplay data 601. Therefore, it is possible to easily reproduce thedisplay state of the content data 63 before the combination or the likeof the display object is performed. In regard to the content data 63displayed by the projector 100, the first display data 601 can be storedwithout omission. That is, the first display data 601 corresponding to adisplayed part of the content data 63 is stored. Therefore, by readingand displaying the first display data 601, it is possible to easilyreproduce the display. In this operation, information regarding the sizeor position of a region cut as the display data 611 in regard to thecontent data 63 is not necessary.

When the display object generated by the object processing unit 34 iscombined with the content data 63 to be displayed, the control unit 30generates the first display data 601 and the second display data 602 andstores the first display data 601 and the second display data 602 in thestorage unit 60. That is, when the display object is combined with theimage based on the content data 63 to be displayed, the projector 100generates the first display data 601 in the state in which no displayobject is combined and the second display data 602 in the state in whichthe display object is combined. Therefore, in regard to the content data63 displayed by the projector 100, the first display data 601 and thesecond display data 602 can be stored without omission, and thus it ispossible to easily reproduce the display state of the content data 63.

When an instruction not to display the display object generated by theobject processing unit 34 is input, the control unit 30 causes theprojection unit 20 to display an image based on the first display data601 stored in the storage unit 60. Thus, the projector 100 canefficiently perform the process of not displaying the display objectusing the first display data 601.

The storage unit 60 may be configured to be able to store the pluralitypieces of second display data 602 in association with one piece of firstdisplay data 601. In this case, for example, the projector 100 can storethe plurality of pieces of second display data 602 corresponding to aplurality of other display objects, and thus can reproduce a displaystate in which the plurality of other display objects are switched andcombined in regard to one piece of content data 63.

In a state in which an image based on the first display data 601 or thesecond display data 602 stored in the storage unit 60 is displayed bythe projection unit 20, the control unit 30 may combine an image basedon the first display data 601 or the second display data 602 as adisplay object to display the image. In this case, the projector 100 cancombine the first image data and the second image data as a displayobject with another image to display the first image data and the secondimage data. Thus, it is possible to reproduce the display state of thecontent data 63 in various forms.

The control unit 30 may cut a part of the content data 63 and cause theprojection unit 20 to display an image based on the cut content data 63.In this case, it is possible to easily reproduce a display state inwhich the projector 100 displays the part of the content data 63.Therefore, when content of the content data 63 is larger than the rangewhich can be displayed on the screen SC, the display state of thecontent data 63 can be reproduced without performing a work ofspecifying a displayed range.

The projector 100 may include the input detection unit 32 that detectsan operation. The object processing unit 34 may generate a displayobject in response to an operation detected by the input detection unit32. In this case, it is possible to generate the display object inresponse to the operation and combine the display object with the imagebased on the content data 63 to display the display object.

The projector 100 includes the position detection unit 50 that detects aposition instruction operation. The input detection unit 32 acquires aninstruction position of the position instruction operation detected bythe position detection unit 50. The object processing unit 34 generatesa display object based on the instruction position acquired by the inputdetection unit 32. Thus, it is possible to generate the display objectin accordance with the position instruction operation and combine thedisplay object with the image based on the content data 63 to displaythe display object.

The projector 100 includes the projection unit 20 that displays an imageby projecting image light to the screen SC. The position detection unit50 detects a position instruction operation in the projection region 10to which the projection unit 20 projects the image light. Thus, theprojector projecting the image light to the screen SC can display animage based on the content data 63, detect a position instructionoperation in the projection region 10, and generate a display object todisplay the display object. It is possible to easily reproduce thedisplay state of the content data 63 displayed by the projector.

The above-described embodiment and modification examples are merelyexamples of specific aspects to which the invention is applied and donot limit the invention. The invention can also be applied as otheraspects. For example, the instructor used to operate the projectionregion 10 is not limited to the pen-type instructor 70. A finger of auser, a laser pointer, an instruction rod, or the like may be used andthe shape or size thereof is not limited.

In the foregoing embodiment, the position detection unit 50 causes thephotographing unit 51 to photograph the screen SC and specifies theposition of the instructor 70, but the invention is not limited thereto.For example, the photographing unit 51 is not limited to theconfiguration in which the photographing unit 51 is installed in thebody of the projector 100 and photographs a projection direction of theprojection optical system 23. The photographing unit 51 may be disposedas a separate body from the body of the projector 100 and thephotographing unit 51 may perform photographing on a lateral side or afront surface of the screen SC. Further, the plurality of photographingunits 51 may be disposed and detect an operation position of the targetdetection unit 54 based on photographic image data of the plurality ofphotographing units 51.

In the foregoing embodiment, the configuration has been described inwhich a synchronization signal is transmitted to the instructor 70 usingan infrared signal emitted by the transmission unit 52 from theprojector 100 to the instructor 70, but the synchronization signal isnot limited to the infrared signal. For example, the synchronizationsignal may be transmitted through radio wave communication or ultrasonicradio communication.

In the above-described embodiment, the example has been described inwhich whether the front end portion 71 of the instructor 70 comes intocontact with the screen SC is determined based on the lighting patternof the transceiver unit 74, but the invention is not limited thereto.For example, whether the front end portion 71 of the instructor 70 ispressed against the screen SC may be determined based on an image of theinstructor 70 and the front end portion 71 shown in the photographicimage data. This configuration can be realized, for example, bydetecting the position of the front end portion 71 based on a pluralityof pieces of photographic image data photographed in differentdirections and detecting an image of the front end portion 71 and animage of the shadow of the instructor 70 from the photographic imagedata.

In the above-described embodiment, the example has been described inwhich the operation of the instructor 70 is detected through thefunction of the position detection unit 50 contained in the projector100, but the invention is not limited thereto. For example, the functionof the position detection unit 50 can also be realized as an apparatusindependent from the projector 100. A form can also be realized in whicha display apparatus other than the projector 100 has the function of theposition detection unit 50 and operates as a position detectionapparatus.

The display apparatus according to the invention is not limited to theprojector 100 that projects an image to the screen SC, as describedabove. Various display apparatuses such as a liquid crystal monitor or aliquid crystal television displaying an image on a liquid crystaldisplay panel, a monitor apparatus or a television receiver displayingan image on a plasma display panel (PDP), and a spontaneous displayapparatus such as a monitor apparatus or a television receiverdisplaying an image on an organic EL display panel called an organiclight-emitting diode (OLED) or an organic electro-luminescence (OEL) areincluded in the display system according to the invention. In this case,the liquid crystal display panel, the plasma display panel, or theorganic EL display panel is equivalent to a display unit and a displaysurface. The display surface is equivalent to the projection region 10or an operation surface and an operation region operated with theinstructor 70.

In the above-described embodiment, the example has been described inwhich the three transmissive liquid crystal panels corresponding to thecolors of RGB are used as the light modulation device 22 modulatinglight emitted by the light source, but the invention is not limitedthereto. For example, three reflective liquid crystal panels may beconfigured to be used or a scheme in which one liquid crystal panel anda color wheel are combined may be used. A scheme in which three digitalmirror devices (DMDs) are used or a DMD scheme in which one digitalmirror device and a color wheel are combined may be configured. Whenonly one liquid crystal panel or DMD is used as the light modulationdevice 22, a member equivalent to a combination optical system such as across dichroic prism is not necessary. A light modulation device canalso be adopted as well as the liquid crystal panel and the DMD as longas the light modulation device can modulate light emitted by the lightsource.

In the above-described embodiment, the projector 100 may stores thedisplay object, instead of the second display date 602, in associationwith the first display data 601.

The functional blocks illustrated in the functional block diagrams ofFIGS. 2, 3, and 4 illustrate functional configurations of the tablets 2and 3 and the projector 100 and specific mounting forms are not limited.That is, it is not necessary to mount hardware corresponding to thefunctional blocks in the drawings and functions of a plurality offunctional units can, of course, also be configured to realize functionsof the plurality of functional units when one processor executes aprogram. Some of the functions realized by software in the foregoingembodiment may be realized by hardware or some of the functions realizedby hardware may be realized by software.

Further, an external apparatus connectable to the projector 100 is notlimited to the tablets 2 and 3. For example, an apparatus capable ofoutputting an image or audio, such as a desktop computer, a portabletelephone including a smartphone, a video/music player, a tunerapparatus of television broadcast, may be used. A specific configurationof an interface connecting an external apparatus to the projector 100 isnot limited. An interface can be applied without limit as long as theinterface can transmit an analog image signal, an audio signal, ordigital data. For example, a server apparatus connected to the tablets 2and 3 and the projector 100 via communication lines may be installed. Inthis case, for example, the projector 100 may be configured to acquirethe control program 61, the setting data 62, and the content data 63,and the like from the server apparatus. Alternatively, the projector 100may be configured to transmit the first display data 601, the seconddisplay data 602, and the input terminal data 603 to the serverapparatus so that the server apparatus stores the data. In this case, adifferent projector from the projector 100 or another type of displayapparatus may be configured to download the first display data 601, thesecond display data 602, and the input terminal data 603 from the serverapparatus and display the first display data 601, the second displaydata 602, and the input terminal data 603. In addition, a specificdetailed configuration of the other units of an apparatus included inthe display system 1 can also be changed arbitrarily in the scope of theinvention without departing from the gist of the invention.

The invention may be embodied according to an aspect of a programperformed by a computer to realize the method of controlling theabove-described projector 100, a computer-readable recording medium thatrecords the program, or a transmission medium that transmits theprogram. A magnetic or optical recording medium or a semiconductormemory device can be used as the recording medium. Specifically, aportable or fixed recording medium such as a flexible disc, a hard diskdrive (HDD), a compact disk read only memory (CD-ROM), a digitalversatile disk (DVD), a Blue-ray (registered trademark) disc, amagneto-optical disc, a flash memory, a card type recording medium canbe exemplified. The recording medium may be a nonvolatile storage devicesuch as a random access memory (RAM), a read-only memory (ROM), or anHDD which is an internal storage device included in each apparatus ofthe display system 1 or an external apparatus connected to eachapparatus.

What is claimed is:
 1. A display apparatus comprising: a display unitthat displays a first image on a display surface; a control unit thatcauses the display unit to display the first image on the displaysurface; an object processing unit that generates a display object; adetection unit that detects an operation; a position detection unit thatdetects a position instruction operation; and a storage unit, whereinthe control unit generates a second image by combining the displayobject generated by the object processing unit with the first imagedisplayed on the display surface, and causes the display unit to displaythe second image, wherein the storage unit stores first display datawhich represents the first image displayed on the display unit, whereinthe storage unit stores second display data which represents the secondimage in association with the first display data, wherein the objectprocessing unit generates the display object in response to theoperation detected by the detection unit, wherein the detection unitacquires an instruction position of the position instruction operationdetected by the position detection unit, and wherein the objectprocessing unit generates the display object based on the instructionposition acquired by the detection unit.
 2. The display apparatusaccording to claim 1, wherein the first display data and the seconddisplay data correspond to an image equivalent to one surface anddisplayed on the display surface by the display unit.
 3. The displayapparatus according to claim 1, wherein when the control unit causes thedisplay unit to display the first image, the control unit stores thefirst display data in the storage unit.
 4. The display apparatusaccording to claim 1, wherein when the control unit combines the displayobject generated by the object processing unit with the first image andcauses the display unit to display the display object, the control unitstores the first display data and the second display data in the storageunit.
 5. The display apparatus according to claim 1, wherein when aninstruction not to display the display object generated by the objectprocessing unit is input, the control unit causes the display unit todisplay an image based on the first display data stored in the storageunit.
 6. The display apparatus according to claim 1, wherein the storageunit stores a plurality of pieces of the second display data inassociation with one piece of first display data.
 7. The displayapparatus according to claim 1, wherein in a state in which the controlunit causes the display unit to display an image based on the firstdisplay data or the second display data stored in the storage unit, thecontrol unit combines the image based on the first display data or thesecond display data as the display object and causes the display unit todisplay the display object.
 8. The display apparatus according to claim1, wherein the control unit cuts a part of content data and causes thedisplay unit to display the first image based on the cut content data.9. The display apparatus according to claim 1, wherein the display unitincludes a projection unit displaying an image by projecting image lightto the display surface, and wherein the position detection unit detectsthe position instruction operation in a projection region to which theprojection unit projects the image light.
 10. A display apparatuscomprising: a display unit that displays a first image on a displaysurface; a control unit that causes the display unit to display thefirst image on the display surface; an object processing unit thatgenerates a display object; a detection unit that detects an operation;a position detection unit that detects a position instruction operation;and a storage unit, wherein the control unit generates a second image bycombining the display object generated by the object processing unitwith the first image displayed on the display surface, and causes thedisplay unit to display the second image, wherein the storage unitstores first display data which represents the first image displayed onthe display unit, wherein the storage unit stores the display object inassociation with the first display data, wherein the object processingunit generates the display object in response to the operation detectedby the detection unit, wherein the detection unit acquires aninstruction position of the position instruction operation detected bythe position detection unit, and wherein the object processing unitgenerates the display object based on the instruction position acquiredby the detection unit.
 11. The display apparatus according to claim 1,wherein, in the second image, the display object overlaps the firstimage.